They say that a lack of daylight is what brings on winter depression, but whenever I come out of the Bolz Conservatory here in Madison, I wonder if the real problem isn't just that all the green is gone. Humans evolved in the African savannah, not the Arctic. Why wouldn't we feel weird surrounded by winter white? The light just feels wrong, without growing things to catch and scatter the sun's rays and warm up the pale, cold blue. A touch of gold helps, too.